The weather may be deceptively warm, and there haven’t been many reported cases of the annual bane of influenza. Nevertheless, its flu season, and that was reason enough for health officials to remind Louisiana residents this week of the importance of getting flu shots.

“The flu vaccine is not a perfect panacea, but it does help prevent unnecessary deaths,” New Orleans Health Commissioner Karen DeSalvo said at a news conference Wednesday at the Ruth U. Fertel/Tulane Community Health Center.

Although many people simply stay at home for a few days when flu strikes, the viral illness can be serious and even fatal among the very young, the very old and people with chronic health problems.

According to the federal Centers for Disease Control and Prevention, about 226,000 Americans become sick enough to need hospital care each year, and as many as 49,000 people in the United States are estimated to die annually of flu-related complications such as pneumonia.

Everyone who is at least 6 months old should be immunized, Health and Hospitals Secretary Bruce Greenstein said. People 2 to 49 years old have the option of getting the vaccine in nasal-spray form as long as they are neither pregnant nor suffering from chronic health problems.

Here’s the reason for that criterion: While shots contain killed virus particles that cannot cause flu, the mist is made with weakened, but living, bits of virus, said Dr. Frank Welch, the medical director of the state health department’s immunization program.

Whatever the format, the goal is the same: to kick-start the production of antibodies by the immune system. Between five and eight days are needed for this process, Welch said.

Unlike previous years, there is an ample vaccine supply, Greenstein said.

The vaccine’s composition varies from year to year, depending on what health experts think will be prevalent during the upcoming flu season. They make this judgment by studying influenza activity in the Southern Hemisphere, where the annual activity begins, “to see what’s coming our way,” Welch said.

Once again, this year’s vaccine contains deactivated bits of the H1N1 virus that causes swine flu, which quickly became dominant when it burst onto the American scene in 2009. The other strains are A/Victoria and B/Wisconsin.

Although local doctors and health-care experts have reported lots of concern about the annual scourge and plenty of interest in being immunized, they said the actual number of Louisianians with flu is low.

“I’m seeing a lot of people getting flu shots, but I haven’t seen that much flu,” said Dr. Jake Rodi, a family-medicine specialist at Ochsner Medical Center -– West Bank. “It tells me that there’s a really bad cold out there or allergies that have been mimicking the flu.”

This observation is bolstered by information that a network of doctors around the state provides to state epidemiologist Raoult Ratard.

About 5 percent of the people these physicians have seen had flu-like symptoms such as aches, a fever above 100 degrees and sore throat, he said. Further testing of samples from these patients has shown that about 40 percent -– 2 percent of the entire group -– have flu.

“So far, it’s very low,” Ratard said.

However, he said, that figure isn’t a reliable indicator of the number of cases in the state, not only because doctors aren’t required to report cases but also because many people with flu avoid the medical system altogether. Instead, they choose to tough it out by staying at home and drinking liquids and eating chicken soup.

The number of people with flu is expected to increase as the flu season progresses, DeSalvo said.

This will happen, she said, not only because people tend to spend more time indoors during cold weather, thereby increasing the potential for spreading infections, but also because hordes of potentially infected people are expected for events such as the Sugar Bowl, the Super Bowl and Mardi Gras.

“We need to be sure we’re all ready,” she said.

Even if someone doesn’t have flu, seeing medical help is a good idea for people who feel they have flu-like symptoms, Rodi said.

“If they don’t have flu, we can administer the vaccine,” he said. “If they have it, we can give them antivirals that can lessen the severity.”